feat: add headless replay support for recorded Playwright tests

- add replay target to Makefile
- introduce scripts/replay.sh for headless test execution
- document replay workflow in README
- clarify requirements and Arch Linux setup

https://chatgpt.com/share/6984a4ca-1118-800f-88f9-1bd0146e922d

Makefile

@@ -19,3 +19,9 @@ install:
 ## 🎥 Run Playwright Codegen (GUI recording)
 codegen:
 	bash scripts/codegen.sh
+
+.PHONY: replay
+
+## ▶ Replay recorded Playwright tests (headless)
+replay:
+	bash scripts/replay.sh